pub fn dp_rec_mc(amount: u32) -> u32 {
    // 定义币种
    let coins = [1, 2, 5, 10, 20, 30, 50, 100];
    
    // 创建dp数组并初始化为一个很大的值，表示未计算的状态
    let mut dp = vec![u32::MAX; (amount + 1) as usize];
    
    // 初始化基准情况，金额为0时，纸币数为0
    dp[0] = 0;

    // 动态规划计算
    for i in 1..=amount {
        for &coin in &coins {
            if i >= coin {
                dp[i as usize] = dp[i as usize].min(dp[(i - coin) as usize] + 1);
            }
        }
    }

    // 最终返回所需的最少纸币数
    dp[amount as usize]
}